The foundation is arguably the most important part of any home. Whether your house has a basement or not, the foundation is what maintains the structural integrity of a house. Unfortunately, there are a lot of issues that challenge that integrity, especially in an older home.
Weather and Hydrostatic Pressure
As those of us who live here know, Lawrenceville sees a lot of rain. The city receives about 52 inches of rain each year. We occasionally see a bit of snow, too, about an inch or so. An abundance of rain changes the moisture content of the soil around the foundation, especially when it reaches saturation levels. Saturated soil weighs more than dry, and builds up what is called hydrostatic pressure, against the foundation. As such, it applies intensive pressure on the walls of a foundation. This causes the foundation to crack and bow, and possibly eventually leads to foundation failure.
Through the years, Georgia has lost most of its topsoil. In the 1930s, the Soil Conservation Act established programs to help reduce erosion. Lawrenceville is located in Georgia’s Piedmont region. The soil here is ultisol, which translates to red clay. The red soil comes from the warm, humid climate taking its toll on acid crystalline, granite, and gneiss rock. Today, the soil is mostly made of clay with little sand left.
Clay soil absorbs and retains moisture, which increases the weight and volume of the dirt and exerts immense and damaging pressure on the foundation of a home. When the soil dries out, it shrinks. That shrinkage creates a void which can lead to the sinking of the foundation.
Some neighborhoods also have trouble with fill dirt. This is the soil brought in by developers to even out a plot of land for building. If the fill is not compacted properly, it could cause foundation problems for the entire neighborhood.
Just as aging is hard on the foundation, it is hard on pipes as well. Broken pipes embedded in slab foundations are not seen. Unless you notice a change in water pressure, that leak can go on undetected, eventually causing damage to the slab. The same applies to basement foundation leaks. Pipe leaks or breakage in crawlspace or pier and beam foundations will further erode the soil and could expedite foundation problems. Any plumbing problems should be addressed immediately before they get worse, leading to bigger problems. Unfortunately, the constant expansion and contraction of the red clay soil in Georgia contributes to breaks in plumbing lines and the resulting leaks.
Trees and Their Roots
We enjoy a lot of trees here in Georgia. Native magnolias, along with other plantings such as Red Maples, Chinese Elm, Chinese Pistache, and Japanese Zelkova are favorites. A problem arises, though, when these large trees are planted too close to the house or a house is erected too close to the trees. Tree roots can cause problems.
As long as a tree lives, its roots will continue to grow outward, looking for more moisture and nutrients. A good rule of thumb is that as far as the branches grow, so do the roots, underground. This can wreak havoc on your home’s foundation.
While the roots themselves may not be strong enough to move a foundation, they continually churn and move the soil. That can cause an elevation of soil in one location and shrinkage in another, enough to alter the conditions under your house. As such, it can alter the stability of your home, causing a portion of or the entire foundation to move.